Process for revivifying filtering materials



Patented Apr. 24, '1934 PATENTI' orrlcr.

- UNITED STATES John D. Haseman, Linton, Ind.

No Drawing.

Serial No. 489,008 2 Claims. (01. 252-2) fullers earth, processed bentonite and the like may be revivified to yield a more eflicient decolorizer with little or no loss of the fine particles and with a minimum expenditure of energy.

The contact method of decolorizing heavy acid stocks as now practiced leaves a gasolene-steam washed fine loose 200 mesh spent material which on being heated to burn out the injurious products blow away by the rapid evaporation of the adsorbed gasolene and consequent tumbling about of the material in burning out the carbon evolved from the lubricating oil and the adsorbed color compounds. The loss is so great that dust collectors are required to catch the particles carried away before they have been properly revivified. Hence with present practices it is impossible to burn out fine spent bleaching materials at a uniform and eificient temperature.

I have discovered that when 25' to 50% by weight of water is mixed with the fine spent bleaching material that it sticks together so that the rapid evaporation of gasolene or burning out of the lubricating oil will not carry away any of the line bleaching material, and that the adhered particles can all be burned out at the same temperatures.

My preference in practice is to mix the dry fine loose bleaching material with fifty percent of water and spread it uniformly on a metal conveyor running through a hooded lead heated furnace' which has increasing temperatures. The

fications can be hottest end or the furnace should be around 900 degrees Fahr. and has provisions for admitting steam as well as the escape of the final carbonizing products. This low temperature carbonizing furnace should preferably be closed and in at least three sections having escape openings or hoods. This preference in practice will not only prevent loss of'fine particles and destroy the injurious catalyzed products of the spent clay but will also activate much of the carbonized material and thereby yield a more efiicient revivified material.

The above description is not to be taken as limiting my invention, but is merely illustrative of r the best method of carrying it out. As will be understood by those skilled in the art, many modimade within the spirit of my inclaim to be.

vention which I I claim:

1. Process which consists in mixing spent bleaching material-with water to make it slightly plastic, driving off the more volatile materials with low temperatures and driving off the injurious catalyzed products at a dull red heat in the absence of air.

2. Process which consists in mixing spent bleaching material with water to make it slightly plastic, driving off the more volatile material with low temperatures, driving off the injurious catalyzed products at a temperature of dull red heat, and activating the retained carbon in absence. of air and the presence of steam. 

